Sökning: "adaptive finite element methods"

Visar resultat 1 - 5 av 49 avhandlingar innehållade orden adaptive finite element methods.

1. 1. Adaptive finite element methods for multiphysics problems

   Författare :Fredrik Bengzon; Mats Larson; Harald van Brummelen; Umeå universitet; []
   Nyckelord :finite element methods; multiphysics; a posteriori error estimation; duality; adaptivity; discontinuous Galerkin; fractional step methods;

   Sammanfattning : In this thesis we develop and analyze the performance ofadaptive finite element methods for multiphysics problems. Inparticular, we propose a methodology for deriving computable errorestimates when solving unidirectionally coupled multiphysics problemsusing segregated finite element solvers. LÄS MER

3. 2. Adaptive Finite Element Methods for Optimal Control Problems

   Författare :Karin Kraft; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element method; discontinuous Galerkin method; optimal control; a posteriori error estimate; dual weighted residual; adaptive; multilevel algorithm; Newton method; control constraint; variational inequality; vehicle dynamics.;

   Sammanfattning : In this thesis we study the numerical solution of optimal control problems. The problems considered consist of a system of differential equations, the state equations, which are governed by a control variable. The goal is to determine the states and controls which minimize a given cost functional. LÄS MER

4. 3. Adaptive Finite Element Methods for Optimal Control Problems

   Författare :Karin Kraft; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dual weighted residual; adaptive; Newton method; variational inequality; vehicle dynamics.; multilevel algorithm; discontinuous Galerkin method; a posteriori error estimate; finite element method; optimal control; control constraint;

   Sammanfattning : In this thesis we study the numerical solution of optimal control problems. The problems considered consist of a systemof differential equations, the state equations, which are governed bya control variable. The goal is to determine the states and controls which minimize a given cost functional. LÄS MER

5. 4. Adaptive Finite Element Methods for Compressible Two-Phase Flow

   Författare :Erik Burman; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; adaptive finite element methods; two-phase flow; compressible flow; conservation laws; hyperbolic systems; a posteriori error estimates; streamline diffusion; stability analysis; quantitative error control; adaptive algorithms; quantitative error control;

   Sammanfattning : In this thesis we develop, apply and analyse adaptive finite element methods with error control for compressible flow problems, focusing in particular on two-phase flow. The adaptive algorithms, aiming at quantitative error control with efficient use of computational resources, are based on a posteriori error estimates, where the error is estimated in terms of the computed solution, the local mesh-size and certain stability factors. LÄS MER

7. 5. Adaptive Finite Element Methods for Reactive Flow Problems

   Författare :Robert Sandboge; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; convection-diffusion-reaction problems; posteriori error estimates; adaptive finite element methods; ; adaptive finite element methods;

   Sammanfattning : We present and analyze adaptive finite element methods with reliable and efficient error control for a variety of convection-diffusion-reaction problems. The adaptive methods are based on a posteriori error estimates, where the error is estimated in terms of the residual of the computed solution, the mesh size and multiplicative factors measuring certain stability properties of an associated linearized dual problem. LÄS MER